Operation and maintenance manual

Troubleshooting Symptoms Charts QSB4.5 and QSB6.7
Page TS-28 Section TS - Troubleshooting Symptoms
Engine Power Output Low
Cause Correction
STEP 9
Charge air cooler is restricted or leaking
.............
Inspect the charge air cooler for air restrictions or
leaks. Refer to Section 4.
OK
Go To Next Step
STEP 10
Fuel leak
.............
Check the fuel lines, fuel connections, and fuel
filters for leaks. Check the fuel lines to the supply
tanks. Refer to the OEM service manual.
OK
Go To Next Step
STEP 11
Air in the fuel system
.............
Check for air in the fuel system. Tighten or replace
the fuel connections, fuel lines, fuel tank
standpipe, and fuel filters as necessary.
OK
Go To Next Step
STEP 12
Fuel supply is not adequate
.............
Check the flow through the filter to locate the
source of the restriction. Refer to the OEM service
manual.
OK
Go To Next Step
STEP 13
Fuel return restriction excessive
.............
Inspect the fuel return lines for restrictions. Refer
to the OEM service manual.
OK
Go To Next Step
STEP 14
Fuel filter or fuel suction line is restricted
.............
Replace the fuel filter. Refer to Section 5. Check
the fuel suction line for restriction Section 5.
OK
Go To Next Step
STEP 15
Vehicle parasitics are excessive
.............
Check the vehicle brakes for dragging,
transmission malfunction, cooling fan operation
cycle time, and engine-driven units. Refer to the
OEM service manual.
OK
Go To Next Step
STEP 16
Lubricating oil level above specification
.............
Check the oil level. Verify the oil pan capacity. Fill
the system to the specified level. Refer to Section
V.
OK
Go To Next Step
STEP 17
Contact a Cummins® Authorized Repair Facility